The present invention relates to cultured cells and a tissue-culturing method, and particularly to cultured cells of the Australian laurel (including house-blooming mock orange, Japanese pittosporum and mock orange), Pittosporaceae and a method for culturing tissues of the Australian laurel, Pittosporaceae by using the cultured cells.
Tissue culture of higher plants have been recently investigated, and techniques for culturing plant tissues taken out from leaves, stems, roots, etc. in large quantities have been noted. If a plant piece cut is placed in a culture medium such as agar or liquid containing a nutrient, a mass of cells swell up from the cut portion. This is called xe2x80x9ccallusxe2x80x9d.
In general, cells of different tissues, for example, tissues of a root and a leaf differ from each other in shape and function. This results from a phenomenon that the cells gradually differentiate with growth. However, the callus continues to grow, while being adventive and undifferentiated.
Ordinarily, in order to propagate plants, seeds or cuttings must be planted. Growing thereof is largely influenced by soils and environments. However, the culture of the callus is not influenced by changes in soils or environments. Further, the callus more fast grows than the ordinary plants. When the callus is supplied with a hormone or a chemical material for promoting germination or rhizogenesis, it becomes a complete plant.
In order to culture tissues of such calluses, methods for culturing tissues of trees such as poplars or eucalyptus are known.
However, the trees for which the tissue culture has been established are limited to kinds of timers such as poplars and eucalyptus. This is one of partially because it is difficult to grow or radicate other kinds without appropriate hormones.
The Australian laurel, Pittosporaceae is a plant belonging to Pittosporaceae for buckbushes and boulevard trees, and a boulevard tree planted in a road center strip. The Australian laurel, Pittosporaceae is strong against environmental pollution and saline resistant. In order to assuredly and speedily supply such plants being strong against environmental pollution, the tissue culture is effective. However, a method for stably proliferating the Australian laurel, Pittosporaceae in a large quantity has not been established.
Under these circumstances, it is an object to provide cultured cells and tissue culture to establish stable mass proliferation and transformation system for the Australian laurel, Pittosporaceae.
In order to accomplish the above object, the present inventors repeatedly effected fundamental researches with respect to conditions suitable for inducing callus-formation and redifferentiation of the Australian laurel, Pittosporaceae. As a result, the inventors discovered the cultured cells and the tissue-culturing method according to the present invention.
The Australian laurel, Pittosporaceae cultured cell is an undifferentiated cell and is obtained by culturing a part of a tissue of the Australian laurel, Pittosporaceae in a culture medium containing thidiazuron (TDZ) in an amount effective for inducing a callus of the Australian laurel, Pittosporaceae tissue.
Following are preferred embodiments of the Australian laurel, Pittosporaceae cultured cells according to the present invention. Any combination thereof are considered to be preferred embodiments of the invention, so long as such will afford no adverse effect.
(1) The Australian laurel, Pittosporaceae tissue is selected from the group consisting of a stem, a leaf, a germ cell and a root.
(2) The cultured cell is a tissue having an age of less than 8 weeks after sowing a Australian laurel, Pittosporaceae seed.
(3) The Australian laurel, Pittosporaceae tissue is a tissue obtained by aseptically growing the Australian laurel, Pittosporaceae seed.
(4) The Australian laurel, Pittosporaceae tissue is a tissue in which a foreign material is introduced into an explant of the seedling of the Australian laurel, Pittosporaceae.
(5) The foreign material is at least one selected from the group consisting of a hereditable material, a protein, an organelle, a physiologically active material and an indicator.
(6) The hereditable material is at least one selected from the group consisting of a DNA, a RNA, an origonucleotide, a plasmid, a chromosome, a artificial chromosome, an organelle DNA and a nucleic acid analog.
(7) The medium further contains naphthaleneacetic acid (NAA).
The present invention further relates to a method for regenerating a plantlet of a Australian laurel, Pittosporaceae, said method comprising the step of subculturing the cultured cell as mentioned above in a culture medium containing thidiazuron (TDZ) in an amount effective for inducing a callus of the Australian laurel, Pittosporaceae tissue.
The following are preferred embodiments of the Australian laurel, Pittosporaceae plantlet-regenerating method.
(1) The culture medium further contains naphthaleneacetic acid (NAA).
(2) The culture is a WP culture.